System Method for Interlocking Support Blocks

ABSTRACT

A system and method for forming a filter media support system with dual locking mechanisms. The support system comprises two or more interlocking rows of support blocks. One or more slides and one or more guides protrude from the side walls of the blocks. Each guide is conformed to receive one slide from a neighboring block forming a first locking joint. The side walls also comprise one or more posts and one or more sockets. Each post is conformed to fit within one socket of a neighboring block, forming a second locking joint. 
     In one embodiment the method for assembling the support system comprises aligning a slide of a first support block with a guide of a second support block. The slide of the first support block is vertically moved into the guide of the second support block. Force is applied so that the posts snap-lock into the sockets.

PRIORITY CLAIM

This is a U.S. National Stage application under 35 U.S.C. 371 of PCTapplication No. PCT/US2006/005456, filed on Feb. 15, 2006, anddesignating the United States. The entire disclosure of this PCTapplication No. PCT/US2006/005456 entitled “System and Method forInterlocking Support Blocks,” is incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to a support system for a filter mediasystem. More particularly, the present invention relates to a system andmethod for interlocking filter media support blocks.

BACKGROUND

Water, wastewater, and industrial filtration units typically have anunderdrain system for supporting filter media and spacing the filtermedia apart from the bottom of the filter. In addition to providingsupport for the filter media, the underdrain system serves two primarypurposes: to collect the filtered water that passes through the mediaand to uniformly distribute backwash water, backwash air, or acombination of both, across the filter.

Formations of support blocks are often used construct the underdrainsystem. The support blocks may be made of pre-cast concrete blocks orconcrete filled plastic jacketed blocks. The high-strength concreteblocks are placed side-by-side and end-to-end in the bottom of thefilter to form a “false bottom.” The blocks provide support for thefilter media and are shaped to collect the filtered water that passesthrough the media.

In operation, a media filter will periodically require cleaning bybackwashing the filter. In addition to shaping for collection, theblocks have conduits, commonly known as laterals, to allow for thepassage of air or water used as a backwash. Piping, such as air headers,is part of the backwash air distribution system. Backwash water isbrought into the system by flumes. Air headers bring in pressurized air,which is distributed into the laterals by pipes from the top of theheaders, through the flumes and into the laterals.

During backwash operations, air is forced through the air distributionpipes and into the air laterals of the underdrain blocks. Thepressurized air can be used as a backwash or combined with water for anair/water backwash. The pressurized air/water combination causes thefiltered water to be passed upward through the media with sufficientvelocity to prevent filter problems such as mud balls, filter cracking,agglomeration buildup on the media grains, and inactive areas within thefilter. The underdrain blocks also form a barrier to physically separatethe filter media from the air distribution pipes underneath the blocks.Separating the filter media from the air distribution pipes prevents thefiner particles of the filter media from clogging of the orifices in thepipes.

Problems can occur during backwash because the upward pressure of theair and/or water against the blocks is too forceful. Sometimes thepressure can fall within a range of 2 psi to 6 psi. Such strong pressuretends to dislocate the blocks, a process known as uplift. When upliftoccurs, filter media drops onto the pipes and damages theinfrastructure. Repairing such damage is costly. In addition, the costsof emptying the filter and realigning the blocks are also expensive. Theprocess is labor intensive and requires substantial downtime of thefilter. As a consequence, there is a need for a support system thatresists uplift.

In the existing systems for filter media support, several types ofsupport blocks systems have been used. In U.S. Pat. No. 6,143,188 toJantsch et al., grout is used to fill the gaps between the blocks. Othersystems simply rely on the weight of the blocks to prevent blockmovement. In U.S. Pat. No. 6,325,931 to Roberts, side rails function tohelp align the blocks side-to-side in the filter basin. The side railson one side are offset from the side rails on the other side to allowthe rails to overlap with the rails of an adjacent block to preventuplift.

One further example of an underdrain system, U.S. Pat. No. 5,160,614 toBrown, comprises a series of modular, interconnected air duct blocks.The row of air duct blocks extends transversely to a plurality oflaterals. The laterals are defined by the connection of individualunderdrain blocks in parallel adjacent rows. The air duct blocks areinterconnected such that interiors of the separate air duct blocks arein fluid communication with one another to supply backwash gas through asingle source of gas supply.

Existing underdrain block designs offer only a limited amount ofbackwash stability and some are difficult to assemble. Because stabilityin the support system is important to avoid damage to theinfrastructure, there is a need for an improved underdrain system thatis easily assembled and will limit the movement of the underdrain blocksduring backwash procedures in both the vertical and horizontaldirections.

DEFINITIONS

For the purposes of this invention, a guide is defined as a device forsteadying or directing the motion of a slide.

For the purposes of this invention, a slide is defined as an extensionthat is guided by one or more parts within which it slides.

SUMMARY

The present invention provides stability against the horizontal andvertical movement of the support blocks caused by uplift forces duringbackwash procedures. To resolve the problem caused by uplift, thepresent invention provides a dual locking system that resists bothhorizontal and vertical movement of the blocks. Advantageously,interlocking slides and guides form a first locking joint, Postspositioned on the side walls of the support blocks form a second lockingjoint when inserted into sockets of a neighboring support block. Theposts and sockets are held in place by interlocking slides and guides.The second locking joints formed by the posts and sockets resistvertical movement of the blocks.

The support system is easily assembled because, in one embodiment, thesupport blocks can be interlocked by vertical assembly. The slide of oneblock moves downwardly into the guide of another. In this manner, nohorizontal space, in which to lay out and slide the support block, isneeded. This is a benefit when a filter support system needs to beassembled in a tight space.

In another embodiment, the support system of the present inventioncomprises two or more interlocking rows of support blocks. Each supportblock comprises a shell. The shell comprises a first side wall, a secondside wall, a first end wall, a second end wall, a top wall, and a bottomwall. One or more slides protrude from the first side wall. One or moreguides protrude from the second side wall. Each guide is conformed toreceive one slide from a neighboring support block, so that as theblocks are aligned in rows, the slides on one row of blocks are insertedinto the guides of an adjacent row of blocks.

Advantageously, each guide comprises a first projection and a secondprojection distal from the first projection and the slide is shaped toclosely fit between the first projection and the second projection. Thefirst side wall defines one or more sockets. The second side wallfurther comprising one or more posts. Each post is conformed to fitwithin one socket of a neighboring support block. As the slides areslipped into the guides, each post is snap-locked into a socket.

In one embodiment of the method of this invention, the method ofassembling the support system comprises aligning a slide of a firstsupport block with a guide of a second support block. The slide of thefirst support block is vertically moved into the guide of the secondsupport block. Each support block has a first wall and a second sidewall. The posts from the second side wall are snap locked into thesockets of the first side wall.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of one embodiment of the support systemillustrating two support blocks.

FIG. 2 is a side view of the first side wall of a support block showingthe ends of the slides and the sockets.

FIG. 3 is a side view of the second side wall of the support blockshowing the guides and the posts.

FIG. 4 is a top view of both a fan shaped slide form and T-shaped slideinterlocked with complementary guides.

FIG. 5 is a side view of several embodiments of the post.

FIG. 6 is a three dimensional end view of both the end walls of thesupport block.

DETAILED DESCRIPTION

Referring now to FIG. 1, a top view of one embodiment of a media supportsystem for a filter is shown. The support system is used to provide afalse bottom for the filter. The false bottom provides a space for theinfrastructure, backwash piping laterals, and sumps. The false bottomalso protects the infrastructure from media filtering down towards thebottom. The support system can be used in a wastewater filter system.

The support system comprises two or more interlocking rows of supportblocks 2, 4. Multiple rows of support blocks will often be used to formthe false bottom of the filter. A row is formed by support blocks placedend to end. Each support block 2 comprises a shell 6. The shell 6comprises a first side wall 8, a second side wall 10, a first end wall12, a second end wall 14, a top wall 16, and a bottom wall 18 (FIG. 2).In one embodiment, the shell is made of a plastic material. The shellforms a cavity which may be filled with material to increase the weightof the block. The weight of the blocks helps resist uplift forces.Examples of suitable fill materials include gravel, cement, and sand.

Advantageously, the interlocking support system having blocks locked inadjacent rows uses the combined weight of the connected blocks to resistthe uplift forces. The present invention comprises a dual locking systemthat resists both horizontal as well as vertical movement of the blocks.In one embodiment, the interlocking mechanism comprises one or moreslides 20 protruding from the first side wall 8. One or more guides 22protrude from the second side wall 10. Each guide 22 is conformed toreceive one slide 31 from a neighboring support block. Each guide 22comprises a first projection 24 and a second projection 26 distal fromthe first projection 24. The slide is shaped to closely fit between thefirst and second projections.

The interlocking blocks are aligned side-by-side so that the guides 22of the block in a first row face the slides in a second row. As theblocks are placed on the floor of the filter, the guides 22 and slides31 are aligned and the slide 31 moves between the first and secondprojections 24, 26 of the guide 22, forming the first locking joint tointerlock the blocks. The placement of the blocks continues until thefalse bottom is completed and each row interlocks with an adjacent row.The interlocking of one row of blocks with another row helps the supportsystem resist uplift and shifting caused by the backwash procedure.

To further secure the interlock of the blocks, the first side wall 8defines one or more sockets 28. The second side wall 10 furthercomprises one or more posts 30. Each post 30 is conformed to fitsecurely within one socket 33 of a neighboring support block 4 to formthe second locking joint.

The guides, slides, posts, and sockets 20, 22, 30, 31, 32 that form thedouble interlock mechanism may be either molded into the side walls 8,10 of the blocks or attached as separate pieces. The molded interlockmechanisms are formed as features of the plastic blocks when they aremanufactured. The molded features are formed from the side wallsthemselves rather than being separate pieces added to the side walls.When parts 20, 24, 26, 30, 31 are formed from separate pieces, they areattached by any suitable attachment means, such as an adhesive or screwattachment.

In one embodiment, the support blocks 2 comprise at least two guides 22,at least two slides 31, at least two posts 30, and at least two sockets33. The guides 22, slides 31, posts 30, and sockets 33 can be positionedadjacent to the end walls 12, 14 of the support blocks, rather thanclose to the mid point of the support block. Positioning theseinterlocking parts adjacent to the end walls decreases movement of thesupport blocks.

FIG. 2 illustrates a detailed side view of one embodiment of the supportblock 2 where each slide 20 comprises an end surface 34. Each endsurface 34 of a slide defines one socket 28. In this embodiment the post30 can be positioned between the projections 24, 26 of the guide 22.When the slides of one row of blocks locks into the guides of a secondrow of blocks, the post 30 within each guide 22 interlocks with a socket33 on the end surface of each slide 31 to further secure the block andform the second locking system. In this arrangement, the guide 22 andslide 31 work to align the post 30 and socket 33.

Additionally, the guide 22, slide 31, post 30, and socket 33 worktogether to snap-lock the blocks together. When the slide 31 is insertedinto the guide 22, the post 30 contacts the end surface 34 of the slide.Due to the elastomeric nature of the support block, as force is appliedto continue the movement of the slide, the support block flexes to allowthe motion to continue. The flexing occurs in the side walls 8, 10, theguide 22, the slide 31, or any combination of the three. When the post30 and socket 33 align, the flexing stops and the post 30 is forced intothe socket 33, snap-locking the post 30 into the socket 33.

Reversing the snap-locking of the post 30 into the socket 33, to unlockthe blocks is more difficult than engaging the post and socket becausethe post is held in the socket by the engagement of guide 22 and slide31. While in the socket 33, the post 30 can not push against the endsurface 34 of the slide to cause the flexing necessary to remove thepost 30 from the socket 33.

The engagement of the post into the socket resists the vertical forcesassociated with uplift. When the post is in the socket, the overlappingareas of the post and socket prevent the independent upward movement ofone block alone. When one block attempts to lift upward, its posts andsockets are restrained by the posts and sockets of the adjacent blocks.

Referring now to FIG. 3, in one embodiment, the first projection 24 ofthe guide and the second projection 26 of the guide are verticallyaligned. This allows the slide 31 to engage the guide 22 by movingvertically into the guide 22. Moving and aligning the support blocks maybe done either manually or with assistance of a lifting machine, such asa crane or backhoe. Vertical engagement of guide and slide allow thesupport system to be assembled with greater ease than horizontalengagement. Vertical engagement requires less working area thenhorizontal engagement because the guide and slide are aligned directlyabove one another rather than offsetting the blocks and sliding theentire block. Additionally, in vertical engagement, gravity will assistin providing the downward force necessary to snap-lock the post 30 intothe socket 33.

Referring now to FIG. 4, in one embodiment of the support system, eachguide 22 forms a first locking joint 200 with one slide 31 of aneighboring support block. The first locking joint 200 resistshorizontal movement of the support blocks. Forming the first lockingjoint 200 causes the post 30 of one block to protrude into one socket ofa neighboring block 33 forming the second locking joint. In oneembodiment, the slide can be fan-shaped 210. In an alternate embodiment,the slide is T-shaped 220. Both the fan-shaped 210 and T-shaped 220slides, along with their complementary guides 22, form the first lockingjoint 200 that resists the forces horizontally pulling the neighboringblocks apart. The shape of the guides 22 allows the slides 31 to easilymove into the guides 22 in a direction tangential to the side walls ofthe blocks, however, when the slides 31 and guides 22 are T-shaped orfan-shaped, the guide 22 will pull against the slide 31 to prevent theblocks from pulling apart.

Referring now to FIG. 5, in one embodiment of the support system, eachpost is cylindrically-shaped 500 and each socket 33 is shaped to form aclose fit with the post 500. In a further embodiment, thecylindrically-shaped post 500 has sloped end surface 510. In stillanother embodiment, the cylindrically-shaped post 500 comprises arounded end surface 520. Alternatively, the post and socket may besubstantially semi-spherically shaped 530. The sloped and rounded endsurfaces 510, 520, 530 assist in the engagement of the post and socket,by reducing the surface area in contact between the post 30 and endsurface 34 of the guide. This reduces friction forces resisting themovement of the post 30.

Referring now to FIG. 6, in one embodiment of the support system, thefirst end wall 12 comprises a first tab 42 and a second tab 44. Thefirst tab 42 is horizontally aligned to the second tab 44. The secondend wall 14 comprises a third tab 46. The third tab 46 is positioned tofit between the first tab 42 and the second tab 44 of a neighboringsupport block. The engagement of tabs on the end walls of the supportblocks also aids to resist the horizontal movement of the blocks.

Assembling the filter media support system of the present invention isoften performed on-site. In one embodiment of the method of interlockingsupport blocks for a filter system, the method comprises aligning aslide 31 of a first support block with a guide 22 of a second supportblock. The slide 31 of the first support block is moved vertically intothe guide 22 of the second support block. While moving and aligning thesupport blocks may be performed in any reasonable manner, often thesupport blocks will be moved manually. A crane, backhoe, or otherlifting device may also be employed to assist in moving the blocks.

While the force of gravity may be enough to engage the blocks, themethod may further comprise applying a downward force to the firstsupport block until a post 30 on the second support block snap-locksinto a socket 33 on the first support block. In an additionalembodiment, the method comprises fitting one tab 46 located on an endwall of the first support block may be between two tabs 42, 44 on an endwall of an adjacent support block.

To assemble the entire support system which forms the false bottom ofthe filter, the methods of this invention may be repeated as many timesas necessary.

While the system an method of the invention has been shown and describedwith reference to several embodiments, it will be understood by thoseskilled in the art that various changes in form and detail may be madetherein without departing from the spirit and scope of the invention.The described embodiments are presented for the purposes of illustrationand not limitation; the present invention is limited only by the claimsthat follow.

1. A support system for a filter comprising: two or more interlockingrows of support blocks; each support block comprising a shell, the shellcomprising a first side wall, a second side wall, a first end wall, asecond end wall, a top wall, and a bottom wall; one or more slidesprotruding from the first side wall; one or more guides protruding fromthe second side wall, each guide conformed to receive one slide from aneighboring support block to form a first locking joint; each guidecomprising a first projection and a second projection distal from thefirst projection, the slide shaped to closely fit between the firstprojection and second projection; the first side wall defining one ormore sockets; and the second side wall further comprising one or moreposts, each post conformed to fit within one socket of a neighboringsupport block to form a second locking joint.
 2. The support system ofclaim 1 wherein each post is positioned within one guide.
 3. The supportsystem of claim 2 wherein each slide comprises an end surface, each endsurface defining one socket so that the post within the guide interlockswith the socket on the end surface of the slide.
 4. The support systemof claim 1 wherein the first projection and second projection arehorizontally aligned
 5. The support system of claim 1 wherein the slideis fan-shaped.
 6. The support system of claim 1 wherein the slide isT-shaped.
 7. The support system of claim 1 wherein each guide forms thefirst locking joint with one slide of a neighboring support block, andeach post protrudes into one socket of a neighboring block to form thesecond locking joint.
 8. The support system of claim 1 wherein each postis cylindrically-shaped and each socket is shaped to form a close fitwith the socket.
 9. The support system of claim 8 wherein thecylindrically-shaped post comprises a sloped end surface.
 10. Thesupport system of claim 9 wherein the cylindrically-shaped postcomprises a rounded end surface.
 11. The support system of claim 1wherein the post and socket are substantially semi-spherically shaped.12. The support system of claim 1 wherein the guides and slides aremolded within the side walls.
 13. The support system of claim 1 whereinthe first end wall comprises a first tab and a second tab, the first tabhorizontally aligned to the second tab; and the second end wallcomprises a third tab positioned to fit between the first tab and thesecond tab of a neighboring support block.
 14. The support system ofclaim 1 wherein the filter system is a wastewater filter system.
 15. Thesupport system of claim 1 wherein each support block comprises at leasttwo guides, at least two slides, at least two posts, and at least twosockets.
 16. The support system of claim 15 wherein each guide ispositioned adjacent an end of the second side wall, and each slide ispositioned adjacent an end of first side wall.
 17. A support block for afilter system comprising: a shell, the shell comprising a first sidewall, a second side wall, a first end wall, a second end wall, a topwall, and a bottom wall; one or more slides protruding from the firstside wall; one or more guides protruding from the second side wall, eachguide conformed to receive one slide from a neighboring support block;each guide comprising a first projection and a second projection distalfrom the first projection, same as claim
 1. each slide comprising an endsurface, the end surface defining a socket; and the second side wallfurther comprising one or more posts, each post positioned within oneguide, and each post is conformed to fit within one socket of aneighboring support block.
 18. The support block of claim 17 wherein thefirst projection and second projection are horizontally aligned.
 19. Thesupport block of claim 17 wherein posts and sockets arecylindrically-shaped.
 20. The support block of claim 19 wherein thecylindrically-shaped post comprises a sloped end surface.
 21. Thesupport block of claim 20 wherein the post is shaped to snap-lock intothe socket.
 22. The support block of claim 17 wherein the guide andslide are molded within the side walls.
 23. The support block of claim17 wherein the first end wall comprises a first tab and a second tab thefirst tab horizontally aligned to the second tab; and the second endwall comprises a third tab positioned to fit between the first tab andthe second tab of a neighboring support block.
 24. The support block ofclaim 17 wherein the block comprises at least two guides, at least twoslides, at least two posts, and at least two sockets.
 25. A method ofinterlocking support blocks for a filter system comprising: aligning oneor more slides of a first support block with one or more guides of asecond support block; and vertically moving the one or more slides ofthe first support block into the one or more guides of the secondsupport block.
 26. The method recited in claim 25, further comprisingapplying a downward force to the first support block until a post on thesecond support block snap-locks into a socket on the first supportblock.
 27. The method recited in claim 25, wherein the filter systemcomprises multiple rows of support blocks and the method furthercomprises the step of interlocking one row of support blocks with anadjacent row of support blocks according to the method of claim 25.